[Studies on hyperthermia and radiation treatment of uterine cancer using multicellular tumor spheroid]

Anticancer effects of hyperthermia and radiation on uterine cancer cells were studied using multicellular tumor spheroids and monolayer cultured cells. Cell lines used were SKG-3a(uterine cervical epidermoid carcinoma), HeLa-S3 (uterine cervical adenocarcinoma) and HEC-59 (uterine corpus adenocarcinoma). All cell lines grown in monolayer culture have similar growth rates, but as spheroids, their growth rate are HeLa-S3 greater than HEC-59 greater than SKG-3a cells. The radiosensitivity of all cell lines in monolayer are as follows according to dose-survival relationships. :HEC-59 greater than HeLa-S3 greater than SKG-3a cells. Survival assay to hyperthermia on SKG-3a and HEC-59 cells resulted in no response from 37 degrees to 41 degrees C and in cytotoxicity over 42 degrees C. There is no difference in sensitivity to hyperthermia between the two types of cells. The responses of three cell lines grown as spheroids in hyperthermia and radiation demonstrated that the combination therapy is not effective on the SKG-3a cell, but induced a 1.3-fold effectiveness ratio in HEC-59 and 1.6-fold in HeLa-S3 cells, i.e. more cytotoxicity than with radiation alone. These results suggests that hyperthermia and radiation employed together may be more effective on radioresistant adenocarcinoma cells than on radiosensitive epidermoid carcinoma cells.